I feel you, I felt dismissed so many times in the past both by close people and professionals; it was frustrating/infuriating, it plunged me into a worse mental state over the years because my issues (thoughts/emotions) remained unattended and my confusion grew ("am I fine or not? what the Hell is happening?")...

One thing that Transpersonal Therapy, CBT and DBT seem to have in common (at least, to my knowledge) is Mindfulness. Have you tried any kind of mindful exercises?

Previously you mentioned that the main issue is that most of your emotions and thoughts remain on the negative side, correct? And that maybe the environment you're in is to blame but you can do little about changing your external situation presently.

I'm no expert, but it seems to me that the problem within may lie in the fact that you haven't paid enough attention to your emotions and thoughts to find out what triggers them, how long they last and why, etc. Since you seem to be logically-driven, perhaps you've been pushing these emotions/thoughts into your subconscious instead, and they're getting cramped. Mindfulness can help bring them back to the surface (consciousness) so you can "listen" to them, realize what needs aren't being met, what is hurting you, what is robbing you of your peace. Also, to analyze them, and (perhaps) eventually bring some healthy mental discipline to transform them by locating and addressing their root(s).

All of this is just a suggestion, in case you're interested in what has been helping me:

Since I have no money to seek for professional help (and I'm a bit discouraged by the bad experiences anyway), I'm keeping a private journal, paying particular attention to my emotions/thoughts during the day; I include my dreams as well, but that may be optional for others. I write twice a day, once right after I wake up and again before bed. I also meditate afterwards for a bit to empty my head and discipline/exercise my mind.

As you externalize your feelings/thoughts in this or any other way (perhaps posting here in the forum), keep in mind that you're looking for the root of your problem (this is your goal), not just to dwell in a loop on its symptoms. It may take time, but it's not lost time, it's time that you're using to nourish yourself. I remind myself that it's a need not a luxury, when I don't have time I make sure I do it for at least 10 -15 min. It will help you to vent meanwhile you're making sense, and keep a record of your daily evolution. Also, who knows, if you find a counsellor fit for you, the journal could also come in handy to share things you have recorded before. Etc.

Hope you find this useful, and hope you feel better soon...